Computational Semantics and Pragmatics Autumn 2014 Raquel Fernández Institute for Logic, Language & Computation University of Amsterdam
Outline for this week Dynamic semantics for dialogue. • Introduction to a prominent dialogue semantics theory: Ginzburg’s KoS. • Treatment of particular phenomena in KoS: non-sentential utterance, metacommunication (other- and self-repair). • Marked homework coming on Thursday. • Choose a project topic by the end of Thursday. • Please choose a slot for the project meetings next week asap. Raquel Fernández CoSP 2014 2 / 24
Interaction and Grammar • It is uncontroversial that spoken dialogue is the primary form of language (also from the point of view of language acquisition). • However, it is still controversial to assume that interaction is built into the grammar. • The dominant paradigms in grammar and semantics have, on the whole, abstracted away from interaction, viewing it as somebody else’s problem. • Given the state of the art, typical conversations (fragmentary, disfluent, etc) still constitute a significant challenge to formal grammar of just about any theoretical flavour. Raquel Fernández CoSP 2014 3 / 24
Interaction and Grammar Some example from the BNC, abridged: Ann: Can you hear the birds singing? Listen. James: Er (pause) yeah. Ann: Can you hear? Bryony: I hear birds singing. Ann: Yes. –––––––––––––––––––––––– Ann: Well put it on the draining board and I’ll wash it and then put it back James: Right, I’ll see ya tonight Ann: Mhm, mhm –––––––––––––––––––––––– Tim: Those pink things that af after we had our lunch. Dorothy: Pink things? Tim: Yeah. Er those things in that bottle. Characterising the meaning of these constructions necessarily involves notions of interaction: Need formal theory that provides notions such as ‘current issue under discussion’, ‘acknowledgement of understanding’, ‘ask intended reference of other’s utterance’ Raquel Fernández CoSP 2014 4 / 24
Ginzburg’s KoS Jonathan Ginzburg (2012) The Interactive Stance: Meaning for Conversation [KoS ≈ conversation-oriented semantics ] • A theory of meaning for spoken interaction that can, in particular, account for non-sentential utterances, and characterise the potential for misunderstanding. • We’ll be able to see only a snapshot of the framework. KoS is based on the dynamic strategy to meaning pioneered by Stalnaker, Lewis, Kamp, Heim, Barwise, Groenendijk and Stokhof et al. • the meaning of a linguistic form is explicated in terms of the effect its use has on commonly shared “contextual resources”. • this suggests thinking of context as structured by resources which conversational participants keep track of Raquel Fernández CoSP 2014 5 / 24
Ginzburg’s KoS • KoS provides a theory of context for conversation by means of which NSUs and metacommunication can be analysed formally. • Main questions: ◮ How is context structured? ◮ How does context evolve? • Other comprehensive accounts of a theory of context for dialogue include work in the PTT framework (e.g. Poesio & Traum 1997, 1998, Poesio & Rieser 2010) and work within Segmented Discourse Representation Theory (SDRT) (e.g. Asher & Lascarides 2003, 2008). Raquel Fernández CoSP 2014 6 / 24
A Single Context? Classic semantics operates under the assumption that perfect communication obtains — nothing go wrong, interpretation leads to an identical update of the interlocutors’ information states. • D. Lewis (1968): Whenever S is uttered, the utterer intends to communicate p and the hearer acquires the belief p . • Equal Access to Context : As a conversation proceeds a shared context (the common ground) emerges: A has her turn, reaches a transition relevance point (TRP); Then either A proceeds or B takes over from the common ground point at which A spoke. It seems a plausible assumption: e.g., A can make an initial utterance, a query, which either A or B can follow up on: A(1): Who should we invite to the conference? A(2): Perhaps Noam, huh? B(2): Perhaps Noam, huh? Raquel Fernández CoSP 2014 7 / 24
A Single Context? However, these examples illustrate that the contextual possibilities for resolving the fragment ‘Bo?’ are distinct for speaker and addressee: A: Who does Bo admire? B: Bo? – reading 1: Does Bo admire Bo? – reading 2: Are you asking who BO (of all people) admires? / Who do you mean ‘Bo’? A: Who does Bo admire? Bo? – reading 1: Does Bo admire Bo? – reading 2: Did I say ‘Bo’? Turn Taking Puzzle (Ginzburg 1997): The resolution of the bare ‘Why?’ phrase changes according to who keeps or takes over the turn. A: Which members of this audience own a parakeet? A: Why? (= Why own a parakeet?) B: Why? (= Why are you asking which members of this audience own a parakeet?) Raquel Fernández CoSP 2014 8 / 24
Context in KoS • In KoS, there is actually no single context. • Instead of a single context, analysis is formulated at a level of information states, one per conversational participant. • The total information state, with two components: one public (the dialogue gamebord) and one private. � � DGB Private • We will be concerned with the DGB. Raquel Fernández CoSP 2014 9 / 24
Context in KoS: the DGB • The dialogue gameboard (DGB) represents information that arises from publicized interactions. • DGB (initial definition): spkr: Ind addr: Ind Facts : Set(Prop) Moves : list(IllocProp) QUD : poset(Question) • The speaker/addressee roles serve to keep track of turn ownership. Raquel Fernández CoSP 2014 10 / 24
The Dialogue GameBoard • FACTS represents the shared knowledge conversationalists utilise during a conversation (information that can be embedded under presuppositional operators). ◮ initial common ground: 7th October, Amsterdam, cloudy,. . . ◮ facts about content and form of (parts of) the utterance A: Did Mark send you a love letter? B: No, though it’s interesting that. . . — you refer to Mark/my brother/our friend — you bring up the sending of love letters — ask about Mark’s epistolary habits — that the final two words you just uttered start with ‘l’. ◮ Not all these facts can be picked up in ellipsis / anaphora. B: No, why? (= why are you asking whether Mark sent me a love letter; cannot mean: why do you refer to Mark/my brother/our friend, why do you bring up the sending of love letters etc) B(3b): No. Don’t you think that’s a bit over inquisitive? (‘that’ = your asking me whether Mark sent me a love letter) Raquel Fernández CoSP 2014 11 / 24
The Dialogue GameBoard Does FACTS contain only semantic information? • Confirmation readings require partial syntactic parallelism: A: I phoned him. B: him? / #he? A: Did he phone you? B: he? / #him? • Information pertaining to syntactic and phonological aspects of an utterance becomes presupposed after the utterance has been grounded at some level (not merely the utterance’s content). • We need fine-grained representations that allow for this ( phon/syn information may fade away faster than semantics). • We’ll come back to this later. • This point has also been argued for extensively by Massimo Poesio, see e.g. Poesio & Traum, 1997; Poesio & Rieser, 2010. Raquel Fernández CoSP 2014 12 / 24
The Dialogue GameBoard • MOVES keeps track of the dialogue acts made. • It is useful to single out the Latest-Move, a distinguished fact that characterises the most recent move made. • The main motivation for this is to segregate from the entire repository of presuppositions information on the basis of which coherent reactions could be computed. Raquel Fernández CoSP 2014 13 / 24
The Dialogue GameBoard • QUD: (mnemonic for Questions Under Discussion): questions that constitute a “live issue”. That is, questions that have been introduced for discussion at a given point in the conversation and not yet been resolved or abandoned. • There are additional, indirect ways for questions to get added into QUD, the most prominent of which is during metacommunicative interaction (more on Thursday). • Being maximal in QUD (MAX-QUD) corresponds to being the current ‘discourse topic’ and is a key component in the theory. • QUD and MAX-QUD are key elements of KoS. Raquel Fernández CoSP 2014 14 / 24
The meaning of ‘yes’ As an example, let’s consider how the DGB could explicate the meaning of a propositional lexeme like “yes”. Ann: Can you hear the birds singing? Listen. James: Er (pause) yeah. Ann: Can you hear? Bryony: I hear birds singing. Ann: Yes. • Hypothesis: the meaning of ‘yes’ is the proposition introduced by Latest-Move into the context . • A cursory examination of any conversational corpus will attest that this description covers a high percentage of the occurrences of ‘yes’. • Nonetheless, the description is intrinsically incomplete. . . Raquel Fernández CoSP 2014 15 / 24
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